Malcolm Gladwell tells us about Operation Mincemeat, a caper undertaken by British intelligence to fool the Hitler and the Nazis into thinking the Allied invasion of mainland Europe would come from through Greece and not Sicily.
It did not take long for word of the downed officer to make its way to German intelligence agents in the region. Spain was a neutral country, but much of its military was pro-German, and the Nazis found an officer in the Spanish general staff who was willing to help. A thin metal rod was inserted into the envelope; the documents were then wound around it and slid out through a gap, without disturbing the envelope’s seals. What the officer discovered was astounding. Major Martin was a courier, carrying a personal letter from Lieutenant General Archibald Nye, the vice-chief of the Imperial General Staff, in London, to General Harold Alexander, the senior British officer under Eisenhower in Tunisia. Nye’s letter spelled out what Allied intentions were in southern Europe. American and British forces planned to cross the Mediterranean from their positions in North Africa, and launch an attack on German-held Greece and Sardinia. Hitler transferred a Panzer division from France to the Peloponnese, in Greece, and the German military command sent an urgent message to the head of its forces in the region: “The measures to be taken in Sardinia and the Peloponnese have priority over any others.”